$bg:#fff;
$ppr:750px/15/1rem;
@mixin trancen() {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

@mixin tranl() {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
}

@mixin trant() {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
}
